Rockwell Automation FactoryTalk Metrics User Guide - Manual (Page 242)

Chapter 7 Advanced Reporting Topics
The fields contain values that are derived from more than one
record from one or more detail fields. Summary values are
typically obtained either by grouping multiple records or by
applying a summarization function (like SUM or AVG) to the
records being summarized.
For example, you can create a summary derived field by
summing up two fields of your choice, dividing one by the
other, and then multiplying the result by 60 seconds.
For details, see "Create Summary Derived Fields (page 247)".
You can add a user-derived field to an existing report data source,
however, it is recommended that you create a new report data source
when creating user-derived fields.
For more information on creating a report data source, see "Create a
Report Data Source (page 237)".
After you create a user-derived field, you can include it in a report.
Detailed text reports cannot contain summary derived fields.
However, both summary and detailed text reports can contain
detailed derived fields.
When creating a report, a detailed derived field can be treated like
any actual field. The rule for summary reports is that every column
in the report must be either a grouped column or have a column
function applied to it. A grouped column is used to determine which
records are grouped together to be summarized, and each of the
columns that are not grouped must have a way (a function) to take
multiple values (from multiple records), and calculate a single value
to display on the report.
Derived fields are derived from other data in the database, so it is
useful to know what other data is available for use when you build
the fields. For more information on the most widely used database
tables, see "Workcell History, Event History, and Machine State
Data (page 261)".
242 Rockwell Automation Publication PLTMT-UM001M-EN-P-June 2014